The hijab policy, which would be contested in court and almost certainly be ruled unconstitutional, saw the 53-year-old return to a familiar campaign theme 15 months from the country's 2022 presidential election.
"I consider that the headscarf is an Islamist item of clothing," Le Pen told reporters at a press conference where she proposed a new law to ban "Islamist ideologies" which she called "totalitarian and murderous."
Since taking over France's main far-right party from her father, Le Pen has run twice for the French presidency, losing badly in 2017 to political newcomer Macron in a defeat that she took months to recover from.
But recent polling shows her closer than ever to her ultimate prize and has led to a rash of new speculation about whether the anti-EU, anti-immigration populist could finally enter the Elysee Palace.
Despite recent setbacks for fellow ideologues such as Donald Trump, and Matteo Salvini in Italy, a survey reported earlier this week showed her within striking distance of Macron.
The poll conducted online by Harris Interactive suggested that if a final-round presidential run-off were held today Le Pen would garner 48 percent while Macron would be re-elected with 52 percent, Le Parisien newspaper reported.
"It's a poll, it's a snapshot of a moment, but what it shows is that the idea of me winning is credible, plausible even," Le Pen said at the Friday press conference.
The prospect of a tight race set off alarm bells in the French political mainstream as the dual health and economic crises caused by the coronavirus pandemic sweep across the country.
"It's the highest she has ever been at," said Jean-Yves Camus, a French political scientist specialized in the far-right, while adding that it was "too early to take the polls at face value".
He said Le Pen was benefiting from frustration and anger over the pandemic, with France on the verge of a third lockdown, but also the beheading of a French school teacher by an extremist last October.
"It had a major impact on public opinion," the expert from the Jean-Jaures Foundation told AFP. "And in this area, Marine Le Pen has an advantage: her party is well known for its position denouncing Islamism."